Android:日常学习笔记(7)———探究UI开发(1)

常用控件的使用方法

TextView

说明：TextView是安卓中最为简单的一个控件，常用来在界面上显示一段文本信息。

代码：

    <TextView
        android:id="@+id/text_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:gravity="center"
        android:textSize="24sp"
        android:textColor="#00FF00"
         />

说明：

　　1.match_parent表示让当前控件的大小与其父布局大小一样，也就是由父布局来决定当前控件的大小。

　　2.wrap_content表示让控件中的内容决定控件的大小。

　　3.android:gravity可以用来指定文本的对齐方式。

Button

说明：A button consists of text or an icon (or both text and an icon) that communicates what action occurs when the user touches it.

(按钮是一种可以包含文本或图标或文本和图标信息的用来反馈用户点击事件的控件)

代码：

　　Depending on whether you want a button with text, an icon, or both, you can create the button in your layout in three ways:

• With text, using the Button class:

  <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/button_text"
      ... />

• With an icon, using the ImageButton class:

  <ImageButton
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:src="@drawable/button_icon"
      ... />

• With text and an icon, using the Button class with the android:drawableLeft attribute:

  <Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/button_text"
      android:drawableLeft="@drawable/button_icon"
      ... />

可以加入下句代码解决所有字母都是大写的问题：

android:textAllCaps="false"

 让按钮响应事件

1.第一种方法：在XML种绑定事件

To define the click event handler for a button, add the android:onClick attribute to the <Button> element in your XML layout. The value for this attribute must be the name of the method you want to call in response to a click event. The Activity hosting the layout must then implement the corresponding method.

For example, here‘s a layout with a button using android:onClick:

<?xml version="1.0" encoding="utf-8"?>
<Button xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/button_send"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/button_send"
    android:onClick="sendMessage" />

Within the Activity that hosts this layout, the following method handles the click event:

/** Called when the user touches the button */
public void sendMessage(View view) {
    // Do something in response to button click
}

The method you declare in the android:onClick attribute must have a signature exactly as shown above. Specifically, the method must:

• Be public
• Return void
• Define a View as its only parameter (this will be the View that was clicked)

2.第二种方法：Using an OnClickListener

You can also declare the click event handler programmatically rather than in an XML layout. This might be necessary if you instantiate the Button at runtime or you need to declare the click behavior in a Fragment subclass.

To declare the event handler programmatically, create an View.OnClickListener object and assign it to the button by calling setOnClickListener(View.OnClickListener). For example:

Button button = (Button) findViewById(R.id.button_send);
button.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        // Do something in response to button click
    }
});

EditText

说明：

　　Every text field expects a certain type of text input, such as an email address, phone number, or just plain text. So it‘s important that you specify the input type for each text field in your app so the system displays the appropriate soft input method (such as an on-screen keyboard).

　　Beyond the type of buttons available with an input method, you should specify behaviors such as whether the input method provides spelling suggestions, capitalizes new sentences, and replaces the carriage return button with an action button such as a Done or Next. This lesson shows how to specify these characteristics

代码：

    <EditText
        android:id="@+id/phone"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:hint="默认的提示信息"
        android:maxLines="2"
        android:inputType="phone" />    

 说明：

android:inputType属性决定了这个文本框应该接收和信息哪一类信息。如上图输入发默认切换为 手机号码 显示。

Constant	Value	Description
date	14	For entering a date. Corresponds to TYPE_CLASS_DATETIME | TYPE_DATETIME_VARIATION_DATE.
datetime	4	For entering a date and time. Corresponds to TYPE_CLASS_DATETIME | TYPE_DATETIME_VARIATION_NORMAL.
none	0	There is no content type. The text is not editable.
number	2	A numeric only field. Corresponds to TYPE_CLASS_NUMBER | TYPE_NUMBER_VARIATION_NORMAL.
numberDecimal	2002	Can be combined with number and its other options to allow a decimal (fractional) number. Corresponds toTYPE_CLASS_NUMBER | TYPE_NUMBER_FLAG_DECIMAL.
numberPassword	12	A numeric password field. Corresponds to TYPE_CLASS_NUMBER | TYPE_NUMBER_VARIATION_PASSWORD.
numberSigned	1002	Can be combined with number and its other options to allow a signed number. Corresponds toTYPE_CLASS_NUMBER | TYPE_NUMBER_FLAG_SIGNED.
phone	3	For entering a phone number. Corresponds to TYPE_CLASS_PHONE.
text	1	Just plain old text. Corresponds to TYPE_CLASS_TEXT | TYPE_TEXT_VARIATION_NORMAL.
textAutoComplete	10001	Can be combined with text and its variations to specify that this field will be doing its own auto-completion and talking with the input method appropriately. Corresponds to TYPE_TEXT_FLAG_AUTO_COMPLETE.
textAutoCorrect	8001	Can be combined with text and its variations to request auto-correction of text being input. Corresponds toTYPE_TEXT_FLAG_AUTO_CORRECT.
textCapCharacters	1001	Can be combined with text and its variations to request capitalization of all characters. Corresponds toTYPE_TEXT_FLAG_CAP_CHARACTERS.
textCapSentences	4001	Can be combined with text and its variations to request capitalization of the first character of every sentence. Corresponds to TYPE_TEXT_FLAG_CAP_SENTENCES.
textCapWords	2001	Can be combined with text and its variations to request capitalization of the first character of every word. Corresponds to TYPE_TEXT_FLAG_CAP_WORDS.
textEmailAddress	21	Text that will be used as an e-mail address. Corresponds to TYPE_CLASS_TEXT |TYPE_TEXT_VARIATION_EMAIL_ADDRESS.
textEmailSubject	31	Text that is being supplied as the subject of an e-mail. Corresponds to TYPE_CLASS_TEXT |TYPE_TEXT_VARIATION_EMAIL_SUBJECT.
textFilter	b1	Text that is filtering some other data. Corresponds to TYPE_CLASS_TEXT | TYPE_TEXT_VARIATION_FILTER.
textImeMultiLine	40001	Can be combined with text and its variations to indicate that though the regular text view should not be multiple lines, the IME should provide multiple lines if it can. Corresponds to TYPE_TEXT_FLAG_IME_MULTI_LINE.
textLongMessage	51	Text that is the content of a long message. Corresponds to TYPE_CLASS_TEXT |TYPE_TEXT_VARIATION_LONG_MESSAGE.
textMultiLine	20001	Can be combined with text and its variations to allow multiple lines of text in the field. If this flag is not set, the text field will be constrained to a single line. Corresponds to TYPE_TEXT_FLAG_MULTI_LINE.
textNoSuggestions	80001	Can be combined with text and its variations to indicate that the IME should not show any dictionary-based word suggestions. Corresponds to TYPE_TEXT_FLAG_NO_SUGGESTIONS.
textPassword	81	Text that is a password. Corresponds to TYPE_CLASS_TEXT | TYPE_TEXT_VARIATION_PASSWORD.
textPersonName	61	Text that is the name of a person. Corresponds to TYPE_CLASS_TEXT | TYPE_TEXT_VARIATION_PERSON_NAME.
textPhonetic	c1	Text that is for phonetic pronunciation, such as a phonetic name field in a contact entry. Corresponds toTYPE_CLASS_TEXT | TYPE_TEXT_VARIATION_PHONETIC.
textPostalAddress	71	Text that is being supplied as a postal mailing address. Corresponds to TYPE_CLASS_TEXT |TYPE_TEXT_VARIATION_POSTAL_ADDRESS.
textShortMessage	41	Text that is the content of a short message. Corresponds to TYPE_CLASS_TEXT |TYPE_TEXT_VARIATION_SHORT_MESSAGE.
textUri	11	Text that will be used as a URI. Corresponds to TYPE_CLASS_TEXT | TYPE_TEXT_VARIATION_URI.
textVisiblePassword	91	Text that is a password that should be visible. Corresponds to TYPE_CLASS_TEXT |TYPE_TEXT_VARIATION_VISIBLE_PASSWORD.
textWebEditText	a1	Text that is being supplied as text in a web form. Corresponds to TYPE_CLASS_TEXT |TYPE_TEXT_VARIATION_WEB_EDIT_TEXT.
textWebEmailAddress	d1	Text that will be used as an e-mail address on a web form. Corresponds to TYPE_CLASS_TEXT |TYPE_TEXT_VARIATION_WEB_EMAIL_ADDRESS.
textWebPassword	e1	Text that will be used as a password on a web form. Corresponds to TYPE_CLASS_TEXT |TYPE_TEXT_VARIATION_WEB_PASSWORD.
time	24	For entering a time. Corresponds to TYPE_CLASS_DATETIME | TYPE_DATETIME_VARIATION_TIME.

指定输入法行动

Most soft input methods provide a user action button in the bottom corner that‘s appropriate for the current text field. By default, the system uses this button for either a Next or Done action unless your text field allows multi-line text (such as with android:inputType="textMultiLine"), in which case the action button is a carriage return. However, you can specify additional actions that might be more appropriate for your text field, such as Send or Go.

To specify the keyboard action button, use the android:imeOptions attribute with an action value such as "actionSend" or "actionSearch". For example:

Figure 4. The Send button appears when you declare android:imeOptions="actionSend".

<EditText
    android:id="@+id/search"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:hint="@string/search_hint"
    android:inputType="text"
    android:imeOptions="actionSend" />

You can then listen for presses on the action button by defining a TextView.OnEditorActionListener for the EditText element. In your listener, respond to the appropriate IME action ID defined in the EditorInfo class, such as IME_ACTION_SEND. For example:

EditText editText = (EditText) findViewById(R.id.search);
editText.setOnEditorActionListener(new OnEditorActionListener() {
    @Override
    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
        boolean handled = false;
        if (actionId == EditorInfo.IME_ACTION_SEND) {
            sendMessage();
            handled = true;
        }
        return handled;
    }
})